India rubber vs ebonite

India rubber and ebonite both are nouns.

Word	Noun	Adjective	Verb	Adverb
India rubber	Yes	No	No	No
ebonite	Yes	No	No	No

As nouns, ebonite is a hyponym of India rubber; that is, ebonite is a word with a more specific, narrower meaning than India rubber:

India rubber: an elastic material obtained from the latex sap of trees (especially trees of the genera Hevea and Ficus) that can be vulcanized and finished into a variety of products
ebonite: a hard nonresilient rubber formed by vulcanizing natural rubber

Other hyponyms of India rubber include foam rubber, crepe rubber, cold rubber, hard rubber, vulcanite, Para rubber.

India rubber (noun)	ebonite (noun)
an elastic material obtained from the latex sap of trees (especially trees of the genera Hevea and Ficus) that can be vulcanized and finished into a variety of products	a hard nonresilient rubber formed by vulcanizing natural rubber